Noise suppression circuit for power adapter
First Claim
1. A noise suppression circuit for a power adapter comprising:
- an operational amplifier coupled between an alternating current (AC) neutral line on a first side of the adapter and a direct current (DC) ground line on a second side of the adapter, the first side of the adapter and the second side of the adapter separated by a transformer, wherein;
an output and a first input of the operational amplifier are coupled to the AC neutral line,a second input of the operational amplifier is coupled to the DC ground line, andthe operational amplifier is configured to cause current to flow from the DC ground line to the AC neutral line, or from the AC neutral line to the DC ground line, based on a noise between the AC neutral line and the DC ground line so as to attenuate the noise between the AC neutral line and the DC ground line, the noise being induced into a DC line on the second side of the adapter.
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Accused Products
Abstract
A noise suppression circuit for a power adapter is disclosed. The noise suppression circuit can reduce or eliminate adapter-induced noise that could interfere with an electronic device powered by the adapter. In one example, the noise suppression circuit can include an active circuit to detect and attenuate or cancel the induced noise. In another example, the noise suppression circuit can include an RLC circuit in parallel with the adapter choke to suppress the induced noise at the operating frequencies of the powered electronic device. In still another example, the noise suppression circuit can include a modified adapter Y capacitor connection so as to bypass the adapter choke, thereby reducing or eliminating the choke'"'"'s induced noise.
31 Citations
19 Claims
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1. A noise suppression circuit for a power adapter comprising:
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an operational amplifier coupled between an alternating current (AC) neutral line on a first side of the adapter and a direct current (DC) ground line on a second side of the adapter, the first side of the adapter and the second side of the adapter separated by a transformer, wherein; an output and a first input of the operational amplifier are coupled to the AC neutral line, a second input of the operational amplifier is coupled to the DC ground line, and the operational amplifier is configured to cause current to flow from the DC ground line to the AC neutral line, or from the AC neutral line to the DC ground line, based on a noise between the AC neutral line and the DC ground line so as to attenuate the noise between the AC neutral line and the DC ground line, the noise being induced into a DC line on the second side of the adapter. - View Dependent Claims (2, 3, 4, 5, 6, 12)
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7. A noise suppression circuit for a power adapter comprising:
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an RLC circuit in parallel with a component of the adapter, the RLC circuit and the component being on a first side of the adapter, the RLC circuit configured to suppress noise induced in the component at select frequencies of an adapter voltage on a second side of the adapter, wherein; the first side of the adapter and the second side of the adapter are separated by a transformer, and the RLC circuit comprises; a first resistor, a first inductor and a first capacitor in parallel with the component and coupling an AC live line on a first side of the component and a second side of the component, and a second resistor, a second inductor and a second capacitor in parallel with the component and coupling an AC neutral line on a first side of the component and a second side of the component. - View Dependent Claims (8, 9, 10, 11)
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13. A power adapter for noise suppression comprising:
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a plug configured to connect to a power source; a connector configured to connect to a device; a power circuit configured to receive a first voltage from the power source, to transform the first voltage into a second voltage compatible with the device, and to send the second voltage to the device to power the device; and a noise suppression circuit configured to suppress noise induced in the power circuit, the noise suppression circuit comprising; an operational amplifier coupled between an alternating current (AC) neutral line on a first side of the adapter and a direct current (DC) ground line on a second side of the adapter, the first side of the adapter and the second side of the adapter separated by a transformer, wherein; an output and a first input of the operational amplifier are coupled to the AC neutral line, a second input of the operational amplifier is coupled to the DC ground line, and the operational amplifier is configured to cause current to flow from the DC ground line to the AC neutral line, or from the AC neutral line to the DC ground line, based on a noise between the AC neutral line and the DC ground line so as to attenuate the noise between the AC neutral line and the DC ground line, the noise being induced into a DC line on the second side of the adapter. - View Dependent Claims (14, 15)
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16. A system for noise suppression comprising:
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an electronic device configured to generate signals; and a power adapter configured to power the electronic device, the adapter lacking a plug ground prong and including a noise suppression circuit configured to suppress noise induced in the adapter from interfering with the generated signals of the device, the noise suppression circuit comprising; an operational amplifier coupled between an alternating current (AC) neutral line on a first side of the adapter and a direct current (DC) ground line on a second side of the adapter, the first side of the adapter and the second side of the adapter separated by a transformer, wherein; an output and a first input of the operational amplifier are coupled to the AC neutral line, a second input of the operational amplifier is coupled to the DC ground line, and the operational amplifier is configured to cause current to flow from the DC ground line to the AC neutral line, or from the AC neutral line to the DC ground line, based on a noise between the AC neutral line and the DC ground line so as to attenuate the noise between the AC neutral line and the DC ground line, the noise being induced into a DC line on the second side of the adapter. - View Dependent Claims (17, 18, 19)
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Specification